Influence of non-steroidal anti-inflammatory drugs and disease activity on serum alkaline phosphatase concentrations in rheumatoid arthritis, osteoarthritis, and polymyalgia rheumatica.

The influence of non-steroidal anti-inflammatory drugs (NSAIDs) and of disease activity on the serum alkaline phosphatase concentration was examined in patients with rheumatoid arthritis, osteoarthritis, and polymyalgia rheumatica. Concentrations of serum alkaline phosphatase were similar both in patients with rheumatoid arthritis taking NSAIDs and in those not taking NSAIDs. In patients with osteoarthritis NSAID use was not associated with a significant increase in serum alkaline phosphatase. In rheumatoid arthritis no correlation was found between clinical indices of disease activity and serum alkaline phosphatase concentrations. There was significant correlation with plasma viscosity in rheumatoid arthritis, both in those taking and not taking NSAIDs, and in polymyalgia rheumatica. Serum alkaline phosphatase concentrations are not influenced by NSAIDs. Concentrations correlate with laboratory parameters, but not clinical indices of disease activity.